Release 10.1A: OpenEdge Development:
Programming Interfaces

Methods and attributes

To use the XML read and write features described in this chapter, you use the handle to a temp-table, temp-table buffer, or ProDataSet to access methods and attributes of the object. Table 22–1 describes the available methods.

Table 22–1: XML methods for temp-tables and ProDataSets

Method	Description
READ-XMLSCHEMA( )	Creates a dynamic temp-table or ProDataSet from the specified XML Schema. Or, it can verify an existing 4GL definition against the XML Schema.
READ-XML( )	Loads data into a static or dynamic temp-table or ProDataSet from the specified XML. Optionally, it can create the temp-table or ProDataSet definition or verify the definition against the specified XML Schema.
WRITE-XMLSCHEMA( )	Writes the schema of the specified static or dynamic temp-table or ProDataSet as XSD. Options allow you to control the formatting, encoding, and level of definition detail.
WRITE-XML( )	Writes the data and, optionally, the definition of the specified static or dynamic temp-table or ProDataSet as XML. Options allow you to control the formatting, encoding, and level of definition detail.

The XML related attributes are described in Table 22–2.

Table 22–2: XML attributes for temp-tables and ProDataSets

Attribute	Data type	Applies to	Description
NAMESPACE-URI (Readable and writeable)	CHARACTER	temp-table temp-table buffer ProDataSet	The namespace is a Uniform Resource Indicator (URI) used to uniquely identify attribute and element names and prevent collisions. Elements or attributes with the same name but a different namespace are considered different. This attribute can also be set with the DEFINE TEMP-TABLE, DEFINE BUFFER, and DEFINE DATASET statements using the NAMESPACE-URI option.
NAMESPACE-PREFIX (Readable and writeable)	CHARACTER	temp-table temp-table buffer ProDataSet	The prefix is used to identify elements which belong to the namespace associated with the NAMESPACE-URI attribute. This attribute can also be set with the DEFINE TEMP-TABLE, DEFINE BUFFER, and DEFINE DATASET statements using the NAMESPACE-PREFIX option.
NESTED (Readable and writeable)	LOGICAL	Data-relation	A data-relation defines a parent-child relationship. Normally, data is represented in XML serially, one table followed by the next. Setting the NESTED attribute to TRUE directs Progress to nest the child rows of the relation within the parent row when written as XML. By default, the NESTED attribute is FALSE. The NESTED attribute also causes the XML Schema definitions for the related temp-tables to be nested. This attribute can also be set with the DEFINE DATASET statement using the NESTED option on a DATA-RELATION specification.
XML-NODE-TYPE (Readable and writeable)	CHARACTER	Buffer-field	Specifies the XML representation for the field. It must be a CHARACTER expression evaluating to one of these values: ELEMENT, ATTRIBUTE, TEXT, HIDDEN. If the XML-NODE-TYPE of a buffer-field is ELEMENT, the field is a child element of the temp-table row element in both the schema and instance data. This is the default. If the XML-NODE-TYPE is ATTRIBUTE, the field will be represented as an attribute of the temp-table row element. If XML-NODE-TYPE is TEXT, the field is a text element of the temp-table row. Note: There can only be one TEXT field per table. If there is a TEXT field, there can be no ELEMENT fields, only ATTRIBUTE fields. Tables with text fields cannot be part of a nested DATA-RELATION. If XML-NODE-TYPE is HIDDEN, the field is omitted from both the XML Schema and data during write operations. Note: Buffer-fields that represent arrays must have XML-NODE-TYPE="ELEMENT" or XML-NODE-TYPE="HIDDEN".
XML-DATA-TYPE (Readable and writeable)	CHARACTER	Buffer-field	Specifies the XML Schema data type for the Progress buffer-field object. If the temp-table definition was created from an XML Schema, this attribute is the same as the type attribute from the XML Schema.

NAMESPACE-URI and NAMESPACE-PREFIX interact in a WRITE-XML method call in the following ways:

If NAMESPACE-URI is specified and NAMESPACE-PREFIX is not, the WRITE-XML method writes the XML document using a default namespace (xmlns="namespaceUri"). For example:

DEFINE TEMP-TABLE ttCust NAMESPACE-URI "http://myCompanyServer.com/myNamespace" FIELD CustNum LIKE Customer.CustNum FIELD Name LIKE Customer.Name FORMAT "x(30)".

This example produces XML like this:

<?xml version="1.0"?> <ttCust xmlns="http://myCompanyServer.com/myNamespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <ttCustRow xmlns="http://myCompanyServer.com/myNamespace"> <CustNum>3</CustNum> <Name>Hoops </Name> </ttCustRow> </ttCust>

If both NAMESPACE-URI and NAMESPACE-PREFIX are specified, all elements in the XML document will start with the NAMESPACE-PREFIX. For example,:

DEFINE TEMP-TABLE ttCust NAMESPACE-URI "http://myCompanyServer.com/myNamespace" NAMESPACE-PREFIX "myPrefix" FIELD CustNum LIKE Customer.CustNum FIELD Name LIKE Customer.Name FORMAT "x(30)".

This example produces XML like this:

<?xml version="1.0"?> <myPrefix:ttCust xmlns:myPrefix="http://myCompanyServer.com/myNamespace" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <myPrefix:ttCustRow> <myPrefix:CustNum>3</myPrefix:CustNum> <myPrefix:Name>Hoops </myPrefix:Name> </myPrefix:ttCustRow> </myPrefix:ttCust>

If NAMESPACE-PREFIX is specified and NAMESPACE-URI is not, the WRITE-XML method will ignore the prefix and write the document with no namespace information. The WRITE-XML method behaves as if neither NAMESPACE-URI nor NAMESPACE-PREFIX is specified. For example:

DEFINE TEMP-TABLE ttCust NAMESPACE-PREFIX "myPrefix" FIELD CustNum LIKE Customer.CustNum FIELD Name LIKE Customer.Name FORMAT "x(30)".

This example produces XML like this:

<?xml version="1.0"?> <ttCust xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <ttCustRow> <CustNum>3</CustNum> <Name>Hoops </Name> </ttCustRow> </ttCust>